From: Antti Palosaari <crope@iki.fi>
To: Steven Toth <stoth@kernellabs.com>
Cc: "Antti Seppälä" <a.seppala@gmail.com>,
"Benjamin Larsson" <benjamin@southpole.se>,
Linux-Media <linux-media@vger.kernel.org>
Subject: Re: [RFC PATCH] mn88472: reduce firmware download chunk size
Date: Thu, 19 Feb 2015 18:44:21 +0200 [thread overview]
Message-ID: <54E612E5.2090905@iki.fi> (raw)
In-Reply-To: <CALzAhNUYQeSDeZ5RFqaRm__a6UDXj7EGZi51vACG2injgBeeRA@mail.gmail.com>
On 02/19/2015 06:25 PM, Steven Toth wrote:
>>> I tried loading the driver with polling disabled and it fails completely:
>>>
>>> [ 5526.693563] mn88472 7-0018: downloading firmware from file
>>> 'dvb-demod-mn88472-02.fw'
>>> [ 5527.032209] mn88472 7-0018: firmware download failed=-32
>>> [ 5527.033864] rtl2832 7-0010: i2c reg write failed -32
>>> [ 5527.033874] r820t 8-003a: r820t_write: i2c wr failed=-32 reg=05 len=1:
>>> 83
>>> [ 5527.036014] rtl2832 7-0010: i2c reg write failed -32
>>>
>>> I have no idea why the device behaves so counter-intuitively. Is there
>>> maybe some sorf of internal power-save mode the device enters when
>>> there is no i2c traffic for a while or something?
>>
>>
>> IR polling does not use I2C but some own commands. Could you make more
>> tests. Use rtl28xxu module parameter to disable IR and test. It will disable
>> both IR interrupts and polling. Then make some tests with different IR
>> polling intervals to see how it behaves.
>>
>> I have 3 mn88472 and 1 mn88473 device and all those seems to work fine for
>> me. I don't care to buy anymore devices to find out one which does not work.
>> Somehow root of cause should be find - it is not proper fix to repeat or
>> break I2C messages to multiple smaller ones.
>
> Ack.
>
> Its the job of the I2C controller to manage the I2C bus
> implementation, including any fragmentation needs, not the
> tuner/demod/other driver.
>
> Find and fix the resource contention bug in the bridge and the mn88472
> will work as is. I suspect something is broken with I2C locking.
It uses i2c control messages - single message per single operation.
You will need lock "control message" when it is done using multiple
messages, very typically two bulk message one for request and one for
reply - but that's not the case. Anyhow, it is possible firmware
rtl2832u firmware does not like some "large (larger than single
message)" operation is interrupted...
regards
Antti
--
http://palosaari.fi/
next prev parent reply other threads:[~2015-02-19 16:44 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-02-19 9:13 [RFC PATCH] mn88472: reduce firmware download chunk size Antti Seppälä
2015-02-19 9:43 ` Benjamin Larsson
2015-02-19 10:21 ` Antti Seppälä
2015-02-19 11:53 ` Benjamin Larsson
2015-02-19 15:38 ` Antti Palosaari
2015-02-19 16:01 ` Antti Seppälä
2015-02-19 16:14 ` Antti Palosaari
2015-02-19 16:25 ` Steven Toth
2015-02-19 16:44 ` Antti Palosaari [this message]
2015-02-19 18:42 ` Antti Seppälä
2015-02-19 20:32 ` Antti Palosaari
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